Do you mean shipping as in on a plane or shipping as in the mail?
Either way, my suggestion would be, if you can't afford a ski case, is to get a hold of a large piece of cardboard and make a specialized box for it. The issue with mailing them is that it is considered a "unusual package" and so you get dinged for it. Today I shipped a 6 foot staff from California to Ohio via UPS Ground and it cost me $26.03. Other carriers will be around the same amount. The good news is that I think that there is some freedom of weight with it as their special charge is something like a base 20 pound cost or some such thing.
I've also used two Fed Ex shipping tubes taped together to ship staffs in the past but I have found taking apart cardboard boxes and cutting them to size works best. If you want to make a perfect crease in corrugated cardboard, use the back side of a butter knife or some other blunt edged object and draw it along where you want the crease. You don't have to cut through the cardboard but this indentation is where the cardboard will fold when you bend it.
If this is going to be something you use multiple times for an airplane, you might want to see about getting some of that plastic corrugated board from Taps Plastic and making a case that way.
